Ultrasound devices and methods for needle procedures

ABSTRACT

A technique of controlling a transducer. The method includes transmitting signals to the transducer, receiving signals from the transducer, and automatically adjusting the signals transmitted to the transducer based on characteristic of the signals received from the transducer. The transducer may be an ultrasound transducer. The adjustment of the signal may be performed at least in part by dynamically updating a signal threshold, for example via a proportional-integral-derivative or other type of control loop implemented at least in part by a field programmable gate array. One or more visual, audio, and haptic feedback to a user based on the signals received from the transducer. The signal may be also included a coded excitation communication and/or a Doppler signal. Automatically adjusting the signals transmitted to the transducer may achieve synchronization with an external imaging system. Also, systems that perform the technique.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims benefit of and priority to U.S.Provisional Patent Application Ser. No. 61/674,818 filed on Jul. 23,2012 entitled “Ultrasound Device for Needle Procedures,” the entirecontents of which are hereby incorporated by reference herein. Thepresent application is a continuation-in-part of U.S. patent applicationSer. No. 13/769,146 filed on Feb. 15, 2013 entitled “Ultrasound Devicefor Needle Procedures,” the entire contents of where are also herebyincorporated by reference herein.

BACKGROUND

The present disclosure generally relates to ultrasound imaging systemsand medical devices and more particularly to the use of such systems anddevices for needle procedures such as biopsies, nerve blocks, andvascular access.

Ultrasound is the most common medical imaging modality after X-rayimaging. The benefits of ultrasound are clear: it is safe, relativelyaffordable, and fast. Given these benefits, it is no surprise thatultrasound usage is increasing.

Doctors commonly use ultrasound to guide needle placement in patients.For example, where there is a suspicion of breast cancer, a practitionerwill use ultrasound on a patient to visualize a suspicious lesion andsubsequently guide a needle to acquire a tissue sample from that lesionfor testing. Such needle procedures are typically difficult for a numberof reasons. First, ultrasound image-guided procedures require experthand-eye coordination. Second, even under optimal imaging conditions,ultrasound can be difficult for a number of reasons. The resultingultrasound image does not accurately depict the exact location of tools,such as needles or catheters, due to the specular reflector nature ofthe materials of the tools. Furthermore, ultrasound images can becolorless, speckled, and difficult to interpret. These factors add totime and complexity of ultrasound-guided procedures while decreasingprecision and confidence.

Myriad approaches try to address these and other issues. For example,U.S. Pat. No. 5,329,927 describes a vibrating mechanism coupled to acannula or needle for Doppler enhanced visualization. Such anarrangement unfortunately requires additional workflow steps includinghaving to sterilize and then attach the vibrating mechanism.Furthermore, smaller ultrasound units may not have Doppler capabilityrequired for functionality.

Several needle manufacturers have used echogenic or texturing methods toenhance needle visibility such as that described in U.S. PatentApplication Publication 2012/0059247. The texture is generally adimpling or scoring of a typically smooth surface to reduce the specularreflector properties. Results show that these textured needles onlyprovide slight benefit in ideal conditions.

Another approach to try to effect accurate needle guidance is torestrict the motion of the needle within the ultrasound imaging plane.For example, U.S. Pat. No. 6,485,426 describes a frame that clips ontothe ultrasound imaging probe and biopsy needle to direct the needle.Such an arrangement unfortunately also adds steps to workflow andsterilization. Furthermore, the arrangement severely limits theimportant aspect of range of motion for needle manipulation.

Yet another attempt to improve ultrasound guidance is by way of anelectromagnetic (“EM”) position sensing system to detect the needle tipin relation to the ultrasound imaging probe and then annotate theultrasound image accordingly. Such a system is made by Ultrasonix.However, this system is a proprietary one that requires specificcompatibility between the needles and the imaging system and thereforelimits the range of procedures. Furthermore EM sensing is costly,requires a calibration step, and is prone to registration error with theultrasound image.

Ultrasonix also released a spatial compounding feature for enhancedneedle visualization. This feature relies on enhancing straight linefeatures in the image, and therefore requires the needle to be in theimaging plane to be useful.

A further attempt to improve ultrasound guidance involves a stylethaving an ultrasound transducer associated therewith, wherein the styletis carried within a hollow biopsy needle. Such an arrangement isdescribed in U.S. Pat. Nos. 5,158,088; 4,407,294; and 4,249,539. Inparticular, the stylet is a wired, non-disposable device that signalsacoustically and/or electronically between the tool in question and theultrasound imaging device for ultrasound image enhancement.Unfortunately, this attempt also introduces a number of additional stepsinto the clinical workflow. For example, using the stylet requires anadditional step of placing the stylet into the hollow needle. Moreover,as the stylet is nondisposable, it must be sterilized before each use.In addition, because the stylet must be used along with other tools,only certain types of tools are compatible with the system.

Accordingly, an ultrasound device for needle procedures that is simpleto use, wireless, disposable, accurate, and compatible with pre-existingultrasonic diagnostic imaging systems and devices is therefore desired.

SUMMARY

One exemplary embodiment of the disclosed subject matter includestechniques of controlling a transducer. In some aspects, the techniqueincludes transmitting signals to the transducer, receiving signals fromthe transducer, and automatically adjusting the signals transmitted tothe transducer based on characteristic of the signals received from thetransducer. The transducer may be an ultrasound transducer. Theadjustment of the signal may be performed at least in part bydynamically updating a signal threshold, for example via aproportional-integral-derivative or other type of control loopimplemented at least in part by a field programmable gate array. One ormore visual, audio, and haptic feedback to a user based on the signalsreceived from the transducer. The signal may be also included a codedexcitation communication and/or a Doppler signal. Automaticallyadjusting the signals transmitted to the transducer may achievesynchronization with an external imaging system. Also, systems thatperform the techniques.

This brief summary has been provided so that the nature of the inventionmay be understood quickly. Additional steps and/or different steps thanthose set forth in this summary may be used. A more completeunderstanding of the invention may be obtained by reference to thefollowing description in connection with the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Some non-limiting exemplary embodiments of the disclosed subject matterare illustrated in the following drawings. Identical or duplicate orequivalent or similar structures, elements, or parts that appear in oneor more drawings are generally labeled with the same reference numeral,optionally with an additional letter or letters to distinguish betweensimilar objects or variants of objects, and may not be repeatedlylabeled and/or described. Dimensions of components and features shown inthe figures are chosen for convenience or clarity of presentation. Forconvenience or clarity, some elements or structures are not shown orshown only partially and/or with different perspective or from differentpoint of views.

FIG. 1 is a perspective view of an embodiment of the inventionsdisclosed herein being used by a medical practitioner to help perform abiopsy;

FIG. 2 illustrates aspects of an embodiment of the inventions disclosedherein and particularly the aspect of a drop-in beacon transducer unit;

FIG. 3 illustrates “before and after” ultrasound images wherein theexact location of the needle tip of an embodiment of the inventionsdisclosed herein may be seen on the “after” ultrasound image once adrop-in beacon transducer unit is activated;

FIG. 4 illustrates a threaded housing aspect of a drop-in beacontransducer unit;

FIG. 5 illustrates another aspect and particularly an integrated circuitdisposed between a transducer film and an adhesive layer;

FIG. 6 illustrates a schematic of an exemplary electrical subsystem;

FIG. 7 illustrates another aspect and particularly a needle device witha transducer and an adapter with electrical subsystem;

FIG. 8 illustrates another aspect of the inventions disclosed herein andparticularly a needle device with a transducer and a removable adapterwith electrical subsystem, wherein the adapter is in turn coupled to ahandle;

FIG. 9 illustrates a bayonet-mount aspect of the disclosed inventions;

FIG. 10 illustrates a slide-and-click aspect of the disclosedinventions;

FIG. 11 illustrates a cartridge-mount aspect of the inventions disclosedherein;

FIG. 12 illustrates a mechanically powered vacuum aspect; and

FIG. 13 illustrates a gas-powered vacuum aspect of the disclosedinventions.

FIG. 14 illustrates a needle visualization system aspect of thedisclosed inventions.

FIG. 15 illustrates forming a square shaped beacon signal according toaspects of the disclosed inventions.

FIG. 16 illustrates a block diagram of an electronic system that shapesbeacon signals according to aspects of the disclosed inventions.

FIG. 17 illustrates a block diagram of a part of an electronic systemaccording to aspects of the disclosed inventions.

FIG. 18 illustrates a process flow according to aspects of the disclosedinventions.

FIG. 19 illustrates data captured from a beacon transducer according toaspects of the disclosed inventions.

FIGS. 20 to 22 illustrate threshold detection according to aspects ofthe disclosed inventions.

FIG. 23 illustrates pulse waveform characterization according to asaspect of the disclosed inventions.

FIG. 24 illustrates synchronization with an external system according toaspects of the disclosed inventions.

FIG. 25 illustrates external system timing according to aspects of thedisclosed inventions.

FIG. 26 illustrates a modular flex circuit transducer and fabricationthereof according to aspects of the disclosed inventions.

FIG. 27 illustrates integration of a modular flex transducer componentinto a needle introducer according to aspects of the disclosedinventions.

FIG. 28 illustrates use of aspects of the disclosed inventions with abiopsy needle device.

DETAILED DESCRIPTION

A general problem in the field of needle devices using ultrasound toguide the needle during a needle procedure is an inaccuraterepresentation on an ultrasound imaging display of the actual locale ofthe needle tip within a patient's body. A general solution is anultrasound needle device comprising a needle shaft and a transducerintegrated within a distal end of the needle shaft.

A technical problem in the field of biopsy devices is accurate tissuesampling. A technical solution implementing the spirit of the disclosedinventions is a needle shaft adapted to cut tissue and a transducerdisposed about the distal end of the needle shaft. The transducer may bepart of a drop-in, self-contained beacon unit that fits within theneedle shaft. The transducer may alternatively include electrical leadsconnectable to an electrical subsystem housed within an adapter that isconnectable to a handle. Alternatively, the electrical subsystem may behoused within a handle connectable to the needle shaft by a bayonetmount configuration, a slide-and-click configuration, or a cartridgeconfiguration. The electrical subsystem is preferably configured tocontrol when the transducer emits an ultrasound pulse. The handle mayinclude all or part of a vacuum means for suctioning in tissue disposedat or near a tissue sampling aperture of the needle shaft.

Potential benefits of the general and technical solutions provided bythe disclosed subject matter include a “plug and play” disposabletransducer beacon unit designed for use with a needle shaft. Otherpotential benefits include a disposable needle and transducer uniteasily mountable to an adapter that is in turn easily attachable to ahandle. Further potential benefits include a biopsy device quicklyattachable to a handle that may include efficient mechanical orpneumatic structures for pulling tissue into the device.

A general nonlimiting overview of practicing the present disclosure ispresented below. The overview outlines exemplary practice of embodimentsof the present disclosure, providing a constructive basis for variantand/or alternative and/or divergent embodiments, some of which aresubsequently described.

FIG. 1 is a perspective view of an embodiment of the inventionsdisclosed herein being used by a medical practitioner to help perform abiopsy. The disclosed inventions need not be limited to use for a biopsybut may instead be used in a variety of needle procedures, including butnot limited to nerve blocks, vascular access, and ultrasound-guidedcatheter diagnostic and therapeutic procedures such as ultrasound-guidedablation. As seen in FIG. 1, a practitioner 106 is using an ultrasoundimaging system 100 to extract a tissue sample from a patient 116. Thesystem 100 may include a display 102, computer 104, ultrasound imagingprobe 108, and novel needle device 110 according to one or more aspectsof the inventions disclosed herein.

The display 102 of the ultrasound imaging system 100 displays thereal-time sonogram of the tissue. The practitioner uses this display 102to visualize, for example, a suspected lesion and needle for guidance.It is here where the needle shaft of the needle device 110 is supposedto be visualized going into the suspected lesion. The probe 108 is usedto image the suspected lesion located inside the body of the patient116.

The needle device 110 includes a handle 114 attachable to a needle 112that is adapted to cut tissue and an ultrasound transducer integratedwith the needle 112. The needle 112 is preferably a hollow shaft havinga tissue sampling aperture with one or more sharp surfaces for cuttingtissue. The transducer is preferably integrated near or about one end ofthe needle shaft. “Integrated” means affixed permanently or temporarilyinside or outside the needle shaft, or alternatively a part of theneedle shaft 118.

In use, the practitioner uses the imaging probe 108 (in one hand) toguide the needle device 110 (in the other hand) by viewing theultrasound display 102. The needle device 110 may be vacuum assisted todraw tissue into the tissue sampling aperture. Exemplary vacuum assistmechanisms are illustrated in FIGS. 12 and 13. The needle device 110 maybe a 20 completely disposable or modular device with disposable needleand transducer.

FIG. 2 illustrates aspects of an embodiment of needle device 110 andparticularly a needle 112 having a needle shaft 118 with a distal end120 and a proximate end 122. The shaft 118 is preferably a hollowcylinder formed by walls having a cut-out to create a tissue samplingaperture 124 disposed between the distal and proximate ends 120, 122.The walls of the tissue sampling aperture 124 are preferably sharp forcutting tissue during a biopsy procedure. A drop-in beacon transducerunit 126 is integrated with the needle shaft 118 at or about the distalend 120 near the tip of the shaft 118. The beacon unit 126 contains anultrasound transducer 128 and optionally the supporting electronicsubsystem 130 and/or power supply 132. In this manner, the beacon unit126 may advantageously be a “plug and play” disposable component meantfor integration with existing needle devices.

FIG. 3 illustrates “before and after” ultrasound images wherein theexact location of the tip of a needle of an embodiment of the inventionsdisclosed herein may be seen on the “after” ultrasound image once adrop-in beacon transducer unit 126 is activated. Such an invention isclearly highly valuable to those skilled in the art.

The beacon unit 126 may be bonded, threaded, or otherwise attached orfitted to or within some component of the needle shaft 118 being usedduring the needle procedure. FIG. 4 illustrates a threaded housingaspect of a drop-in unit 126. In particular, FIG. 4 shows that thebeacon unit 126 may comprise a housing 134 with external threading 136and the needle shaft 118 may have internal threading 138 wherein thebeacon unit may be screw-fit within the needle shaft 118 or similararrangement. The housing 134 of the beacon unit 126 may have a hex slot140 or the like for screwing the unit 126 into the walls of the shaft118. Alternatively, the housing 134 may also be the needle shaft 118itself or a sub-component of the needle assembly, as in the case ofbiopsy needles that have multiple components.

A drop-in beacon unit such as that illustrated in FIGS. 2 through 4 maybe fabricated by way of one or more of the following steps. Start with ahollow tube with outer diameter of approximately 3 millimeters andlength of approximately 5 to 10 millimeters. Add an integrated circuitfor the electrical subsystem, such as system 130 illustrated in FIG. 2.Drill a hole in the side of the tube to accommodate wiring (not shown)and transducer (such as that shown in FIG. 2). Run a wire from theintegrated circuit to an electrical interconnect and to the hole andalso to an optional power supply. The power supply may be a small, highvoltage battery 132 that may fit within the self-contained beacon unit126 or in the handle 114. Alternatively, the beacon unit 126 may bewirelessly powered by the use of wireless power technology disclosed byone or more of the following United States patents, each of which isincorporated by reference as if fully disclosed herein: U.S. Pat. Nos.6,289,237; 6,615,074; 6,856,291; 7,027,311; 7,057,514; 7,084,605;7,373,133; 7,383,064; 7,403,803; 7,440,780; 7,567,824; 7,639,994; and7,643,312. Next, fill the hollow tube with non-conductive acousticbacking material (not shown) and cure. If a battery is to be used, addthe battery 132. Then place piezoelectric material in the hole,completing electrical connection with wiring. Finally, create theacoustic bond and coat the unit 126 with parylene.

Instead of a drop-in beacon unit arrangement such as that illustrated inFIGS. 2 through 4, the beacon transponder unit 126 may comprise a filmor flex circuit that is wrapped or bonded onto the needle shaft 118 orneedle sub-component. FIG. 5 depicts an integrated film embodiment of aself-contained beacon unit 126. Turning in detail to FIG. 5, transducer128 may comprise a piezoelectric ultrasound transducer film or material.This film material 142 may either be rigid or flexible with electrodes(not shown) on both the top and bottom surfaces to receive and apply avoltage potential across the transducer 128. An integrated circuit 144may be fabricated on either a substrate such as a silicon wafer orprinted circuit board and be connected to both electrodes of thepiezoelectric transducer film 142. The integrated circuit 144 may becoupled with a logic and/or power source to comprise in whole or in partthe electrical subsystem 130 for the beacon unit 126. An adhesive layeror patch 146 may serve as a coupling interface between the needle shaft118 and beacon unit 126. If the beacon unit 126 is not a self-containedor self-powered unit, electrical leads (not shown) may be incommunication with the film 142. In such case, when the transducer 128receives and sends acoustic pulses from and to the imaging probe 108,the leads will be used to conduct the electrical signals to and from thetransducer 128 to the electrical subsystem 130.

FIG. 6 illustrates a schematic of an exemplary electrical subsystem ofthe disclosed inventions, such as electrical subsystem 130 depicted inFIG. 2. The electrical subsystem 130 may particularly be designed suchthat it is built to receive and send ultrasound pulses automaticallythrough the transducer 128. The electrical subsystem 130 preferably andadvantageously is configured to control when an ultrasound pulse fromthe transducer 128 is to be emitted.

Turning in detail to FIG. 6, a signal from transducer 128 is amplifiedby amplifier 150 and then sent to a high threshold detector 154 and alow threshold detector 152. If the signal is above the low threshold,the field effect transistor 148 is closed and the amplified signal issent back to the transducer 128. However, once the amplified signalreaches above the high threshold, the field effect transistor 156 closesand connects the transmitting line to ground 158 to stop thetransmission of the signal. In this manner, the system 100 sends backultrasound pulses to achieve the desired end result, such as the brightbeacon-like image on the ultrasound imaging monitor depicted in the“after” version of FIG. 3. Further details of an exemplary electricalsubsystem of the disclosed inventions are discussed below with respectto FIGS. 14 to 24.

FIG. 7 illustrates another aspect of an embodiment of the inventionsdisclosed herein and particularly a needle 112 with a transducer 128integrated at a distal end of a needle shaft 118. At the opposite endthereof is an adapter 160 with electrical subsystem 130. The adapter 160has electrical/mechanical connection means 162 for connection to ahandle such as that shown in FIG. 1. The integrated unit illustrated inFIG. 7 is advantageously disposable.

FIG. 8 illustrates another aspect of an embodiment of the inventionsdisclosed herein and particularly a needle device 110 with a transducer128 integrated at a distal end of a needle shaft 118. At the oppositeend thereof is a connector 164 that is attachable to a removable adapter160 with electrical subsystem 130. The adapter 160 is attachable to ahandle 114.

FIG. 9 illustrates a bayonet-mount aspect of the disclosed inventions.As shown in FIG. 9, needle device 110 comprises a needle 112 with needleshaft 118 including a tissue sampling aperture 124, transducer (notshown) disposed at or about aperture 124, adapter 160 withelectrical/mechanical connection means 162 and particularly a bayonetconfiguration thereof, and handle 114 with button 174 for actuating thedevice 110. In association with adapter 160, the connection means 162may comprise one or more of the following: a male mechanicalinterconnect locking mechanism 166, a vacuum channel 168, an electrical(+) lead connect 170, and an electrical (−) lead connect 172. Inassociation with handle 114, the connection means 162 may comprise oneor more of the following: a female mechanical interconnect lockingmechanism 166 a, a vacuum channel 168 a, an electrical (+) lead connect170 a, and an electrical (−) lead connect 172 a.

FIG. 10 illustrates a slide-and-click aspect of the disclosedinventions. As shown in FIG. 10, needle device 110 comprises a needle112, adapter 160 with electrical/mechanical connection means 162, andhandle 114. Connection means 162 may comprise complementary mechanicaland electrical interconnects 178, 178 a that slide and click into oneanother. A vacuum port 176, 176 a enables negative pressure to beapplied to tissue at or about the distal end of needle 112.

FIG. 11 illustrates a cartridge-mount aspect of the inventions disclosedherein. As shown in FIG. 11, needle device 110 comprises a needle 112,adapter 160 with electrical/mechanical connection means 162, and handle114. Connection means 162 may comprise a male cartridge insert 180 atthe end of needle 112 opposite tissue sampling aperture 124 and a femalecomponent 180 a in handle 114. The cartridge insert 180 may contain theelectrical contacts so the electrical subsystem 130 (not shown) in thehandle 114 may be connected to the transducer 128 (not shown) at thedistal tip of the needle shaft 118. FIG. 12 illustrates across-sectional view of another aspect of an embodiment of theinventions disclosed herein and particularly a mechanically poweredvacuum aspect. The integrated tissue-cutting needle device 110 includesa vacuum means in the form of a needle syringe arrangement. Inparticular, as seen in FIG. 12, a plunger barrel or handle 114 containsa spring 182 so when plunger 184 is depressed (barrel is in “empty”position), the spring 182 resists and applies force to push the plunger184 back into the “full” position. The tendency of the plunger 184 toreturn to the “full” position creates negative air pressure in thebarrel chamber. The spring 182 need not be within the barrel chamber, asthe same force may be achieved from a spring 186 between the plungershaft and the outside of the chamber.

The needle device 110 illustrated in FIG. 12 may comprise a cuttingmechanism that may include two nested, concentric thin-walled tubes 188,190. The outer tube 188 ends in a sharp cone-tip 192. A spring 198inside the tip of the outer tube 188 pushes against the inner tube 190.Both tubes 188, 190 may include sampling notches 124, 124 a in the tubewalls 188, 190, positioned so when the inner tube 190 fully compressesthe tip-spring 198, both sampling notches 124, 124 a line up and thecutter is considered in the “open” position. The edges of the samplingnotches 124, 124 a are sharp so when the inner tube 190 slides and thesampling notches 124, 124 a becomes “shut,” the action is like aguillotine, cutting whatever tissue is within the notches 124, 124 a.

To initiate the vacuum and cutting mechanisms, the user must firstdepress the plunger 184 to the “empty position.” The air-tight plunger184, in addition to displacing air from the barrel and compressing theplunger spring 182 or 186, also pushes against the inner needle tube190, which compresses the needle spring 192. With the plunger 184 in thefully depressed position, cams 194, 196 activate to cock each spring182, 186 in their compressed position. One cam 196 engages the plungershaft to hold the plunger 184 in the “empty” position. The other cam 194engages the inner needle tube 190 to hold the cutter window 124 in the“open” position.

With the needle vacuum and cutter cocked, the user then inserts andguides the needle 112 to the appropriate location within the body of thepatient 116. Upon identifying the suspicious lesion, the user engagesthe vacuum by disrupting the plunger-cam 196. This disruption allows thespring 182 to decompress until the next cam-engagement point on theplunger shaft to create negative pressure in the barrel chamber. Thisnegative pressure is continuous to the sampling notch 124 in the needle112, which pulls tissue into the notch 124. If the vacuum pressure isnot sufficient, the user can disrupt the plunger-cam several more timesuntil the spring is fully decompressed.

Once sufficient tissue is pulled into the sampling notch 124, the userthen disrupts the cutter-cam 194. This releases the spring action on theinner cutting tube 190, closing the “guillotine.” With the tissue samplecut, the user removes the needle 112 from the patient 116 and thenremoves the sample from the needle 112.

FIG. 13 illustrates a cross-sectional view of a gas-powered vacuumaspect of an embodiment of the disclosed inventions. In particular, FIG.13 depicts a gas-powered vacuum assisted device sub-component ofultrasound device 110 that may be integrated within the handle 114. Asseen in FIG. 13, handle 114 may contain a high-pressure gas canister 200that may contain liquid carbon dioxide, compressed air, or the like. Thepressure from the gas in this canister 200 is released when a sharp pin202 pierces the canister 202, releasing the gas to press up against thepositive pressure piston 204 coupled to the negative pressure piston 206via the physical connection 210. When the negative pressure piston 206is forced to the right side of FIG. 13, a vacuum is created in thevacuum cylinder 208. This vacuum cylinder 208 extends into the needle112 via a needle vacuum cylinder attachment on the needle 112 where itterminates at the sampling aperture 124. Thus, when the gas canister 200is forced into the pin 202 via the canister button cam 214 uponactuation of button 212, a vacuum is applied to the vacuum cylinder 208in the needle 112. Tissue is then pulled into the sampling aperture 124where a cutting mechanism, such as sharp walls forming the sampleaperture 124, may excise the tissue.

Transducer and Electronic Subsystem

Conventional 2D ultrasound images (B-mode) can be considered a linear orswept raster ensemble of 1D scan lines (A-mode). Basically each scanline is created when the ultrasound imaging probe transmits a focusedpulse of ultrasound energy into the patient and then captures the echoedenergy. The timing and amplitude of the echoes form a single column ofan image of the patient's anatomy. Multiple sequential scan lines coverthe field-of-view to form, column by column, a 2D image. Ultrasoundworks well to image soft tissue. However, needles and other surgicaltools are difficult to image reliably because they behave as specularreflectors. This makes the ultrasound-guided procedure more difficult.

Aspects of the disclosed inventions attempt to enhance ultrasound needlevisualization by selectively triggering return ultrasound pulsesdirected towards the imaging probe upon receiving incident transmitenergy from the appropriate scan lines. The external imaging system'sreceiving beamformer treats these generated pulses as it does all returnecho energy and the end result is a bright, clear “beacon” signalappearing on the imaging system's display. Since the process ofbeamforming in the external imaging system is understood, an electronicsubsystem according to aspects of the disclosed inventions generates atransmit waveform and precisely controlled time points so that thepulses are received by an external imaging system at the appropriatetime and converted into a useful signal that shows the position of theultrasound transducer. For example, the signal may be used to generate aposition “beacon” signal on an external ultrasound or other system'simaging display.

FIG. 14 illustrates a needle visualization system design in an effort toachieve the foregoing. The system includes biopsy needle 300 with beacontransducer 301 and electronic subsystem 302. Transducer 301 andelectronic subsystem 302 preferably form a disposable “plug-and-play”package that can be integrated with existing disposable interventionaltools.

Beacon transducer 301 is mounted in or on needle 300. The transducer(e.g., an acoustic stack and electrical connectors) should be compact inorder to fit into the form factor of the needle. For example, if thetransducer is to fit into a 14 AWG core biopsy needle, all componentsincluding the transducer and connecting cable must be housed inside theinner trocar shaft so as not to interfere with the biopsy needle'stissue sampling mechanism.

More generally, any type of transducer may be used, for example atransducer incorporated into, part of, or otherwise attached to aninstrument used to perform a procedure. For example, the transducer maybe mounted in or on a needle shaft, introducer, dilator, catheter or anyother tool that can be inserted inside the body and guided withultrasound imaging. Aspects of the disclosed inventions may also be usedwith multiple transducers, for example to show two separate locations ona needle (i.e. biopsy needle tip and biopsy needle cutting sheath) orother tool.

An exemplary design and fabrication method for transducer 301 isdiscussed below with respect to FIGS. 25 to 27.

Electronic subsystem 302 receives incoming electrical signals from thetransducer when ultrasonic pulses transmitted by the imaging probe arraythrough the tissue are received. This imaging probe array may be anytype of linear, phase, curved-linear, 2D array, mechanically sweptimaging probe, or other imaging probe device. Using this technique, abright marker may be introduced into the B-mode ultrasound image toindicate the tip or other positions of the needle or interventionaltool.

This image enhancement preferably is achieved through purely acousticenergy transmission techniques without the need to modify the softwareor hardware of the external ultrasound imaging system. As one possibleresult, aspects of the disclosed inventions preferably can work withnearly all ultrasound imaging systems universally. Possible benefits ofsuch broad-ranging applicability include but are not limited to theability to use this beacon visualization system with any externalultrasound imaging system, the ability to use this beacon visualizationsystem with existing devices such as biopsy needles, having more freedomto update external systems without having to update other components,flexibility in choice of imaging systems, and simplified stock control(e.g., of transducers and other equipment). The system furthermorepreferably results in real-time or near real-time imaging, allowing theuser to perform procedures such biopsies and other procedures withoutinterruption to the clinical workflow. In addition, less experiencedtechnicians may be able to use the system because they may not have tolearn how to compensate for “lag” in generated images.

User outputs from or driven by the electronic subsystem may includeimaging information, characteristics about signals sent to and/orreceived from one or more transducers, information derived from some orall of those characteristics, visual display data, audio feedback,haptic feedback, and/or some combination thereof. In some aspects, datafor the outputs may be provided via one or more data output ports suchas GPIB and/or USB ports. Output data may be formatted or otherwiseapplicable to generating a heads-up and/or virtual reality display(e.g., via smartglasses or some other headset) that corresponds withtransducer position relative to an external imaging probe. For example,an indicator light or signal appearing in the user's field of view mayinstruct the user when the transducer(s) and therefore associated needleor other tool is within the imaging plane, thus helping the user guidethe tool throughout a procedure.

In an attempt to achieve the foregoing, the electronic subsystem usesreceived ultrasound pulses to “learn” what type of scanner it is beingused with and then to “pair” with that system by synchronizing a pulsepattern and transmitting a pulse waveform that matches that of theimaging system. Part of the learning process according to aspects of thedisclosed inventions include dynamic threshold detection. Thresholddetection according to aspects of the disclosed inventions includesdetecting depth and position in the azimuth and elevation directionrelative to an imaging probe:

Depth Position:

The needle transducer should have sufficient sensitivity to detectimaging pulse trains up to a depth of 20 centimeters from the probe, thegenerally accepted maximum realistic depth for most applications of thesubject technology. Different maximum depths may be used.

Azimuthal Plane Position:

Aspects of the disclosed invention capture a signal from each scan linepulse within the pulse train of each imaging frame. Within only 1 frame,the pulse repetition frequency (PRF) of the external imaging systempreferably may be calculated by measuring the time between adjacentpulse trains. With each imaging plane, a threshold may be applied todetermine how many scan line pulses are above a threshold. This numbermay be used as an error value for a proportional-integral-derivative(PID) controller. A set point may be establish for the number of scanlines that should be above the fixed threshold, and the error value maybe used to modulate the gain applied to the incoming signal. Thisfeedback control mechanisms preferably ensures that system onlytransmits an excitation pulse to the transducer when the imaging probesscan lines are most directly lined up with the needle transducer. Theintended result is that the imaging probe receives pulses from thetransducer beacon system only when the scan lines are generated when theimaging aperture is centered directly above the needle transducer. Thus,the imaging screen should display a bright beacon signal in theazimuthal plane precisely at the transducer's location.

Elevation Direction:

From a user perspective it is preferably not to see a beacon signal onthe imaging screen when the needle tip itself is not within the imagingplane of the transducer array. Not transmitting a pulse from the needletransducer when the transducer is outside the imaging plane is thereforepreferable. One technique for doing so according to aspects of thedisclosed inventions is to use a fixed amplitude threshold and variablegain modulated by the error of the PID controller.

Some aspects of the disclosed inventions attempt to precisely controlthe critical characteristics of the beacon signal in order to maintain auniform signal at the prices location of the needle tip. Thesecharacteristics and their control mechanisms illustrated in FIG. 15. Inthe figure, block 304 represents an imaging array probe and area 305represents an imaging field for the probe. Beacon signal 306 in theimaging field is characterized by horizontal position 308, verticalposition (depth) 310, signal height 312, and signal width 314. Thesignal also may be characterized by signal brightness and “blinking”frequency. Audio feedback may also be used to provide real-timeinformation to a user about the beacon signal. Control mechanismsassociated with these factors according to aspects of the disclosedinventions include the following:

Beacon Signal Characteristic Control Mechanism Horizontal PositionSelect pulses from within a pulse train set of a single imaging frame tocenter a signal on the actual position of the needle transducer.Vertical Position (Depth) Send transmit pulses so external imaging arraypulse(s) reach a needle transducer at precisely the same time. SignalWidth Select a discrete number of scan lines within an imaging frame towhich the system responds. Signal Height Select a number of transmitwaveform cycles. The transmit signal pulse length and number of cyclesdetermines the total signal height. Signal Brightness Vary a transmitsignal amplitude. In some aspects, signal brightness may be pure whiteon B-mode imaging if the transmit signal is at the top most of thedynamic range of the receive beamformer of the external imaging system.Blinking Frequency Transmit the pulses at calculated intervals, whichmay cause the signal to appear to “blink.” A blinking signal may be moreconspicuous and therefore more useful for identifying a position of aneedle tip that includes a transducer. These intervals can be determinedbased on the frame rate of the external imaging system. For example, bytransmitting for 10 consecutive frames and then not transmitting for 10consecutive frames with a frame rate of 20 Hz the beacon signal willappear to blink at frequency of 1 Hz. Audio Feedback Emit an audiosignal, for example from the electronics subsystem, when the transducer(and therefore needle) is within the imaging plane, thereby helping theuser to keep the needle within the plain throughout a procedure.

The foregoing control mechanisms were successfully tested in conjunctionwith commercial ultrasound scanners. The Appendix to the Specificationshows the results of one such test using a Phillips iu22 scanner withlinear array probe. The various image tiles in the Appendix show thatthese mechanisms have the ability to manipulate a beacon signal in thedepth position as well as the height and width of the signal. TheAppendix forms a part of this disclosure and is hereby incorporated asif fully set forth herein.

Doppler signals may be sent by the electrical subsystem in some aspectsof the disclosed inventions. These signals may be interpreted by theexternal imaging system as echo signals from tissue. The signals may becoded to a certain frequency shift, which may be translated by theexternal imaging system to a velocity and be displayed in an imagingmode such as color Doppler as a red or blue signal, providing enhancedbeacon signal contrast to the user. This doppler signal waveform may beinterpreted by the electric subsystem, which in turn may trigger avisual, auditory, or other cue. Examples of such cues include but arenot limited to particular colors, sounds, haptic outputs, and the like.The cue(s) may provide an enhanced indication of transducer positionduring a procedure.

In some aspects, the electrical subsystem may also transmit codedexcitation pulses in order to send communication signals other than theones used to form a beacon signal. These coded excitation pulses couldcommunicate information such as commands, position and orientationinformation, and/or Doppler signal information.

Aspects of the disclosed inventions adapt to different brands and/ormodels of external imaging systems and respond with a suitable pulsesequence. FIG. 16 illustrates a block diagram of an electronic systemthat may be used to perform such operations. System 320 includesmicroprocessor 322 that communicates with externalcontrol/communications/display unit 324. The microprocessor preferablyperforms the following functions:

-   -   Control interface GUI and buttons.    -   Interface with registers in FPGA    -   Calculate received pulse frequency spectrum and center frequency    -   Control Proportional-integral-derivative (PID) loop        The external control/communications/display unit preferable        provides the following functions:    -   External Control/Communication/Display    -   Receive user input    -   Generate Visual, Audio, Data and Haptic Output

The microprocessor sends and receives data to/from FPGA (FieldProgrammable Gate Array) 326. The FPGA preferably performs the followingfunctions:

-   -   Store control parameters in registers    -   Receive echo data from an analog to digital converter for        storage in a first-in-first-out (FIFO) data buffer    -   Detect pulses based on a threshold    -   Dynamically update the threshold based on percentage of highest        amplitude of received pulse    -   Generate transmit pulse to transducer

The PID control loop includes digital to analog converter 328, time gaincompensation unit 330, band pass filter 332, and analog to digitalconverter 334. The FPGA uses information from the control loop undercontrol of the microprocessor to control pulser 336, which is providedpower by supply 338. The pulser feeds transmit/receive switch 340 oranother interface for transmission of pulses to a needle or other typeof transducer. Received signals from the switch are sent to amplifier342, which in turn are sent to time gain compensation unit 330 in thePID control loop. Thus, feedback is provided to the FPGA forimplementation of the control mechanisms discussed above.

While a PID control loop is illustrated in FIG. 16, aspects of thedisclosed inventions are not limited to a PID control loop. Rather, thesubject technology encompasses medical imaging systems and/or subsystemsthat use learning in order to adapt to different external systems and/orto provide more accurate or real-time imaging information.

Likewise, while FIG. 16 shows use of a microprocessor and FPGA, othertypes of processors may be used. In addition, various of the elementsshown in FIG. 16 may be combined, and certain functions may be dividedamong various elements in different ways from those depicted anddescribed.

Further details of one possible arrangement of FPGA 326 are illustratedin FIG. 17. FPGA 350 includes low pass filter 352, pulse detection unit354, noise rejection unit 356, registers and interface unit 358,threshold and mean update unit 360, FIFO buffer 362, transmit pulsegeneration unit 364, and clock 366. In some aspects, these elementsinteract as depicted in FIG. 17 to perform the functions of FPGA 326discussed above with respect to FIG. 16. Details of some possibletechniques for performing these operations are described below.

FIG. 18 illustrates a process flow according to aspects of the disclosedinventions. Flow 370 includes learning processes 372, system response374, and system control 376. Learning process 372 attempt to learn thepulsing pattern of an external imaging system. System response 374attempts to generate pulse formation and synchronization. System control376 handles user interface controls and user indicators, for exampleinterfaces to audio and visual indicators.

As depicted, learning process 372 includes threshold detection 378,pulse characterization 380, and external system timing 382. Thresholddetection includes the following:

-   -   Compare current pulse(s) to previous pulse(s) from memory    -   Update learning data    -   Control pulse amplitude    -   Control pulse count        Pulse characterization includes the following:    -   Fast Fourier Transform        -   Calculate center frequency        -   Calculate bandwidth    -   Pulse count        External system timing includes the following:    -   Pulse repetition frequency    -   Frame rate

As depicted, system response 374 includes external system timing 384 andpulser 386. External system timing includes the following:

-   -   Construct pulse frame pattern    -   Synchronize transmit with receive pattern        Pulser includes the following:    -   Transmit pulse shape (pulse, sine wave, square wave)    -   Generate pulse with learned pulse frequency    -   Generate pulse with learned pulse count

Transmit/receive switch 388 controls whether pulses are transmitted toor received from transducer 390. In operation, pulses are transmittedand received, information about the received pulses are used during flow370 to determine how to modify the pulses to adapt a particular externalimaging system, pulse characteristics are modified, and pulses are againtransmitted/received.

In more detail, the processing algorithm preferably uses severalcharacterization steps to learn about an external imaging system. FIG.19 shows plots 400, 402, and 404 at three times scales for a signalreceived at a needle transducer from an ultrasound imaging probe. Inplot 400, the signal exhibits a periodicity of ˜27 milliseconds. Thisdemonstrates two successive scan line ensemble frames for an imagingrate of ˜35 frames per second. Plot 402 zooms in on a single frame andthe individual scan line transmit events can be resolved. The amplitudesare based on the spatial focusing of each scan line. Energy directlyfocused at the needle transducer will yield a higher amplitude signalthan transmit energy focused elsewhere. These raster scan lines createone 2D image frame. Plot 404 zooms in on a single scan line, therebyshowing that the received pulse is approximately 1 microsecond inhalf-max duration. The pulse yields a strong primary spike at 633microseconds but reverberations characteristic of “ring-down” are likelycaused by narrow bandwidths. This type of analysis may be used tocharacterize signals to/from a beacon transducer according to aspects ofthe disclosed inventions.

FIGS. 20 to 22 illustrate threshold detection according to aspects ofthe disclosed inventions, for example as may be performed by thresholddetection 378 in FIG. 18. The input to threshold detection may includepulse waveform data, and the output may include qualifying pulse patternand timing. In some aspects, the threshold level is variable and isautomatically raised and lowered in order to have a fixed number ofpulses PASS above the threshold level. By setting a fixed number ofpulses to “Qualify”, the width of the beacon signal may be controlled.FIG. 20 illustrates a threshold level that is too low: too many pulsesqualify. FIG. 21 illustrates a threshold level that is too high: too fewpulses qualify. FIG. 22 illustrates an appropriate threshold level: anappropriate number of pulses qualify.

FIG. 23 illustrates pulse waveform characterization according to aspectsof the disclosed inventions, for example as may be performed by pulsecharacterization 380 in FIG. 18. The input to pulse waveformcharacterization may include pulse waveform data, and the output mayinclude pulse waveform characteristics. In some aspects, the thresholdlevel is variable and is automatically raised and lowered in order tohave a fixed number of pulses PASS above the threshold level. By settinga fixed number of pulses to “Qualify”, the width of the beacon signalmay be controlled. Processing and calculations preferably are performedin an FPGA and/or microprocessor (e.g., microcontroller). The outputpulse waveform characteristics may include, for example, pulsefrequency, pulse amplitude, number of pulse cycles, pulse modulation(frequency or amplitude), and pulse pattern (i.e. multi-cycle dutyfactor, pulse train pattern for Doppler).

FIG. 24 illustrates synchronization with an external imaging systemaccording to aspects of the disclosed inventions. System 408 in FIG. 24includes electronic subsystem 410 according to aspects of the disclosedinventions, for example including features described above. According tosome aspects, the electronic subsystem creates a communications linkwith external visualization system 412 by synchronizing with theexternal system.

For example, by establishing a method of echo data decoding andencoding, the electronics sub-system may be able to encode position datainto its transmitted pulses. These transmitted pulses may be sent by theneedle transducer, received by the external imaging probe, and thenintegrated with the received echo data in the imaging system'sbeamforming process. This technique may be used to transmit data for thepurpose of needle (or other instrument) visualization. In some aspects,the data transfer format is essentially analog acoustic energy pulsestraveling between the ClariTrac transducer and the external ultrasoundprobe.

In more detail, the automated nature of the signal processing depictedin FIG. 24, including the decoding and encoding processes, may permitpairing (i.e., synchronization) with many if not all external imagingsystems. To achieve this pairing, the electronic subsystem according tosome aspects (1) receives and characterize pulses from the externalimaging system probe, (2) generates a transmit pulse waveform, forexample as described above, and (3) transmits it in a patternsynchronized with that of the external imaging system probe. Thesynchronization processes attempts to facilitate production of a clear,stable, and precisely located beacon signal on the external ultrasoundsystem's imaging display. Pairing preferably is possible with externalsystems that use various arrays such as linear and phase arraysoperating in various modes such as B-Mode and Doppler-Mode.

FIG. 25 illustrates external system timing according to aspects of thedisclosed inventions, for example as may be performed by external timing382 in FIG. 18. The input to external timing may include pulse waveformdata, and the output may include an external system pulse pattern. Insome aspects, a new pulser pattern set is created based on the receivedpulse pattern, and techniques according to the subject technology (e.g.,learning and response) continuously adjust the time position of thepulse command signal pattern to synchronize with the external imagingsystem. Box 414 in FIG. 25 illustrates successful shifting of a pulsepattern to synchronize with an external system.

Modular Flex Circuit Transducer

Aspects of the disclosed inventions include a batch fabrication processthat combines flex circuit interconnect technologies with needlefabrication techniques, creating an inexpensive modular solution forultrasound transducer production that may work with a broad range ofexisting needle designs including those currently used by medical devicecompanies FIG. 26 illustrates a modular flex circuit transducer andfabrication thereof according to aspects of the disclosed inventions. Asshown, piezoelectrical (PZT) elements may be laminated in a single flexcircuit panel and subsequently separated to form discrete, modulartransducer components. These components may have the electrodes alreadyconnected and may be ready for integration with a needle assembly.

FIG. 27 illustrates integration of a modular flex transducer componentinto a needle introducer according to aspects of the disclosedinventions. In the figure, individual ultrasound transducer (A) isintegrated into the polymer needle introducer extrusion to form the (B)finished Introducer. The cross section of an 11 AWG polymer extrusion isshown in (C). The introducer's circular inner lumen may accommodate alarge core biopsy needle. This design is intended to allow introducersof various gauges to be made by only changing the polymer extrusionsub-component of the introducer.

FIG. 28 illustrates use of aspects of the disclosed inventions with abiopsy needle device. During a biopsy procedure, the needle andintroducer (A) is advanced to a lesion under the guidance of the beacontransducer. Once the lesion is reached as confirmed by the beacon signalon the imaging screen, the needle core may be (B) extended from theintroducer. To sample the tissue, the (C) sampling aperture may be shutrapidly under the force of a spring loaded mechanism in the biopsyhandle. The needle then may be extracted from the introducer to collectthe tissue sample. The introducer may remain at the lesion locationthroughout the procedure, enabling multiple passes to be performed withthe beacon signal confirming the precise location from where the samplesare taken.

Generality of Invention

While certain embodiments have been described, the embodiments have beenpresented by way of example only and are not intended to limit the scopeof the inventions. Indeed, the novel devices and methods describedherein may be embodied in a variety of other forms; furthermore, variousomissions, substitutions, and changes in the form of the devices andmethods described herein may be made without departing from the spiritof the inventions. For example, the terms “aspect,” “example,”“preferably,” and the like denote features that may be preferable butnot essential to include in some embodiments of the invention. Inaddition, details illustrated or disclosed with respect to any oneaspect of the invention may be used with other aspects of the invention.Additional elements and/or steps may be added to various aspects of theinvention and/or some disclosed elements and/or steps may be subtractedfrom various aspects of the invention without departing from the scopeof the invention. Singular elements/steps (e.g., “unit,” “element,” and“structure”) imply plural elements/steps and vice versa. Some steps maybe performed serially, in parallel, in a pipelined manner, or indifferent orders than disclosed herein. Many other variations arepossible which remain within the content, scope, and spirit of theinvention, and these variations would become clear to those skilled inthe art after perusal of this application. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the inventions.

1. A method of controlling a transducer, comprising: transmittingsignals to the transducer; receiving signals from the transducer; andautomatically adjusting the signals transmitted to the transducer basedon characteristic of the signals received from the transducer.
 2. Amethod as in claim 1, wherein the transducer comprises an ultrasoundtransducer.
 3. A method as in claim 1, wherein the step of automaticallyadjusting the signals transmitted to the transducer is performed atleast in part at least in part by dynamically updating a signalthreshold.
 4. A method as in claim 1, wherein the step of automaticallyadjusting the signals transmitted to the transducer is performed atleast in part by a proportional-integral-derivative control loop.
 5. Amethod as in claim 4, wherein the proportional-integral-derivativecontrol loop is performed at least in part by a field programmable gatearray.
 6. A method as in claim 1, further comprising providing one ormore visual, audio, and haptic feedback to a user based on the signalsreceived from the transducer.
 7. A method as in claim 6, wherein thevisual feedback further comprises virtual reality data.
 8. A method asin claim 1, wherein the signal further comprises a coded excitationcommunication or a Doppler signal.
 9. A method as in claim 1, whereinthe step of automatically adjusting the signals transmitted to thetransducer further comprises synchronizing with an external imagingsystem.
 10. A method as in claim 1, wherein the transducer is mounted inor on a needle shaft, introducer, dilator, or catheter.
 11. A controlsystem for at least one imaging transducer, comprising: at least oneinterface through which signals are transmitted to or received from thetransducer; at least an electronic subsystem including at least onetangible computing element that performs steps including: receivingsignals from the transducer; and automatically adjusting the signalstransmitted to the transducer based on characteristic of the signalsreceived from the transducer.
 12. A system as in claim 11, wherein thetransducer comprises an ultrasound transducer.
 13. A system as in claim11, wherein the step of automatically adjusting the signals transmittedto the transducer is performed at least in part by dynamically updatinga signal threshold.
 14. A system as in claim 11, wherein the step ofautomatically adjusting the signals transmitted to the transducer isperformed at least in part by a proportional-integral-derivative controlloop.
 15. A system as in claim 14, wherein the electronic subsystemincludes at least a field programmable gate array that performs at leastpart of the proportional-integral-derivative control loop.
 16. A systemas in claim 11, wherein the electronic subsystem further provides one ormore visual, audio, and haptic feedback to a user based on the signalsreceived from the transducer.
 17. A system as in claim 16, wherein thevisual feedback further comprises virtual reality data.
 18. A system asin claim 11, wherein the signal further comprises a coded excitationcommunication or a Doppler signal.
 19. A system as in claim 11, whereinthe step of automatically adjusting the signals transmitted to thetransducer further comprises synchronizing with an external imagingsystem.
 20. A system as in claim 11, further comprising the transducerand a needle shaft, introducer, dilator, or catheter in or on which thetransducer is mounted.